/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *  http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.mlizhi.base.codec.language;

import com.mlizhi.base.codec.EncoderException;
import com.mlizhi.base.codec.StringEncoder;


/**
 * Encodes a string into a double metaphone value.
 * This Implementation is based on the algorithm by <CITE>Lawrence Philips</CITE>.
 * <ul>
 * <li>Original Article: <a 
 * href="http://www.cuj.com/documents/s=8038/cuj0006philips/">
 * http://www.cuj.com/documents/s=8038/cuj0006philips/</a></li>
 * <li>Original Source Code: <a href="ftp://ftp.cuj.com/pub/2000/1806/philips.zip">
 * ftp://ftp.cuj.com/pub/2000/1806/philips.zip</a></li>
 * </ul>
 * 
 * @author Apache Software Foundation
 * @version $Id: DoubleMetaphone.java 800153 2009-08-02 22:45:30Z ggregory $
 */
public class DoubleMetaphone implements StringEncoder {

/**
 * "Vowels" to test for
 */
private static final String VOWELS = "AEIOUY";

/**
 * Prefixes when present which are not pronounced
 */
private static final String[] SILENT_START = 
{ "GN", "KN", "PN", "WR", "PS" };
private static final String[] L_R_N_M_B_H_F_V_W_SPACE = 
{ "L", "R", "N", "M", "B", "H", "F", "V", "W", " " };
private static final String[] ES_EP_EB_EL_EY_IB_IL_IN_IE_EI_ER = 
{ "ES", "EP", "EB", "EL", "EY", "IB", "IL", "IN", "IE", "EI", "ER" };
private static final String[] L_T_K_S_N_M_B_Z = 
{ "L", "T", "K", "S", "N", "M", "B", "Z" };

/**
 * Maximum length of an encoding, default is 4
 */
protected int maxCodeLen = 4;

/**
 * Creates an instance of this DoubleMetaphone encoder
 */
public DoubleMetaphone() {
super();
}

/**
 * Encode a value with Double Metaphone
 *
 * @param value String to encode
 * @return an encoded string
 */
public String doubleMetaphone(String value) {
return doubleMetaphone(value, false);
}

/**
 * Encode a value with Double Metaphone, optionally using the alternate
 * encoding.
 *
 * @param value String to encode
 * @param alternate use alternate encode
 * @return an encoded string
 */
public String doubleMetaphone(String value, boolean alternate) {
value = cleanInput(value);
if (value == null) {
return null;
}

boolean slavoGermanic = isSlavoGermanic(value);
int index = isSilentStart(value) ? 1 : 0;

DoubleMetaphoneResult result = new DoubleMetaphoneResult(this.getMaxCodeLen());

while (!result.isComplete() && index <= value.length() - 1) {
switch (value.charAt(index)) {
case 'A':
case 'E':
case 'I':
case 'O':
case 'U':
case 'Y':
index = handleAEIOUY(value, result, index);
break;
case 'B':
result.append('P');
index = charAt(value, index + 1) == 'B' ? index + 2 : index + 1;
break;
case '\u00C7':
// A C with a Cedilla
result.append('S');
index++;
break; 
case 'C':
index = handleC(value, result, index);
break;
case 'D':
index = handleD(value, result, index);
break;
case 'F':
result.append('F');
index = charAt(value, index + 1) == 'F' ? index + 2 : index + 1;
break;
case 'G':
index = handleG(value, result, index, slavoGermanic);
break;
case 'H':
index = handleH(value, result, index);
break;
case 'J':
index = handleJ(value, result, index, slavoGermanic);
break;
case 'K':
result.append('K');
index = charAt(value, index + 1) == 'K' ? index + 2 : index + 1;
break;
case 'L':
index = handleL(value, result, index);
break;
case 'M':
result.append('M');
index = conditionM0(value, index) ? index + 2 : index + 1;
break;
case 'N':
result.append('N');
index = charAt(value, index + 1) == 'N' ? index + 2 : index + 1;
break;
case '\u00D1':
// N with a tilde (spanish ene)
result.append('N');
index++;
break;
case 'P':
index = handleP(value, result, index);
break;
case 'Q':
result.append('K');
index = charAt(value, index + 1) == 'Q' ? index + 2 : index + 1;
break;
case 'R':
index = handleR(value, result, index, slavoGermanic);
break;
case 'S':
index = handleS(value, result, index, slavoGermanic);
break;
case 'T':
index = handleT(value, result, index);
break;
case 'V':
result.append('F');
index = charAt(value, index + 1) == 'V' ? index + 2 : index + 1;
break;
case 'W':
index = handleW(value, result, index);
break;
case 'X':
index = handleX(value, result, index);
break;
case 'Z':
index = handleZ(value, result, index, slavoGermanic);
break;
default:
index++;
break;
}
}

return alternate ? result.getAlternate() : result.getPrimary();
}

/**
 * Encode the value using DoubleMetaphone.  It will only work if 
 * <code>obj</code> is a <code>String</code> (like <code>Metaphone</code>).
 *
 * @param obj Object to encode (should be of type String)
 * @return An encoded Object (will be of type String)
 * @throws EncoderException encode parameter is not of type String
 */
public Object encode(Object obj) throws EncoderException {
if (!(obj instanceof String)) {
throw new EncoderException("DoubleMetaphone encode parameter is not of type String"); 
} 
return doubleMetaphone((String) obj);
}

/**
 * Encode the value using DoubleMetaphone.
 *
 * @param value String to encode
 * @return An encoded String
 */
public String encode(String value) {
return doubleMetaphone(value);   
}

/**
 * Check if the Double Metaphone values of two <code>String</code> values
 * are equal.
 * 
 * @param value1 The left-hand side of the encoded {@link String#equals(Object)}.
 * @param value2 The right-hand side of the encoded {@link String#equals(Object)}.
 * @return <code>true</code> if the encoded <code>String</code>s are equal;
 *  <code>false</code> otherwise.
 * @see #isDoubleMetaphoneEqual(String,String,boolean)
 */
public boolean isDoubleMetaphoneEqual(String value1, String value2) {
return isDoubleMetaphoneEqual(value1, value2, false);
}

/**
 * Check if the Double Metaphone values of two <code>String</code> values
 * are equal, optionally using the alternate value.
 * 
 * @param value1 The left-hand side of the encoded {@link String#equals(Object)}.
 * @param value2 The right-hand side of the encoded {@link String#equals(Object)}.
 * @param alternate use the alternate value if <code>true</code>.
 * @return <code>true</code> if the encoded <code>String</code>s are equal;
 *  <code>false</code> otherwise.
 */
public boolean isDoubleMetaphoneEqual(String value1, 
  String value2, 
  boolean alternate) {
return doubleMetaphone(value1, alternate).equals(doubleMetaphone
 (value2, alternate));
}

/**
 * Returns the maxCodeLen.
 * @return int
 */
public int getMaxCodeLen() {
return this.maxCodeLen;
}

/**
 * Sets the maxCodeLen.
 * @param maxCodeLen The maxCodeLen to set
 */
public void setMaxCodeLen(int maxCodeLen) {
this.maxCodeLen = maxCodeLen;
}

//-- BEGIN HANDLERS --//

/**
 * Handles 'A', 'E', 'I', 'O', 'U', and 'Y' cases
 */
private int handleAEIOUY(String value, DoubleMetaphoneResult result, int 
 index) {
if (index == 0) {
result.append('A');
}
return index + 1;
}

/**
 * Handles 'C' cases
 */
private int handleC(String value, 
DoubleMetaphoneResult result, 
int index) {
if (conditionC0(value, index)) {  // very confusing, moved out
result.append('K');
index += 2;
} else if (index == 0 && contains(value, index, 6, "CAESAR")) {
result.append('S');
index += 2;
} else if (contains(value, index, 2, "CH")) {
index = handleCH(value, result, index);
} else if (contains(value, index, 2, "CZ") && 
   !contains(value, index - 2, 4, "WICZ")) {
//-- "Czerny" --//
result.append('S', 'X');
index += 2;
} else if (contains(value, index + 1, 3, "CIA")) {
//-- "focaccia" --//
result.append('X');
index += 3;
} else if (contains(value, index, 2, "CC") && 
   !(index == 1 && charAt(value, 0) == 'M')) {
//-- double "cc" but not "McClelland" --//
return handleCC(value, result, index);
} else if (contains(value, index, 2, "CK", "CG", "CQ")) {
result.append('K');
index += 2;
} else if (contains(value, index, 2, "CI", "CE", "CY")) {
//-- Italian vs. English --//
if (contains(value, index, 3, "CIO", "CIE", "CIA")) {
result.append('S', 'X');
} else {
result.append('S');
}
index += 2;
} else {
result.append('K');
if (contains(value, index + 1, 2, " C", " Q", " G")) { 
//-- Mac Caffrey, Mac Gregor --//
index += 3;
} else if (contains(value, index + 1, 1, "C", "K", "Q") && 
   !contains(value, index + 1, 2, "CE", "CI")) {
index += 2;
} else {
index++;
}
}

return index;
}

/**
 * Handles 'CC' cases
 */
private int handleCC(String value, 
 DoubleMetaphoneResult result, 
 int index) {
if (contains(value, index + 2, 1, "I", "E", "H") && 
!contains(value, index + 2, 2, "HU")) {
//-- "bellocchio" but not "bacchus" --//
if ((index == 1 && charAt(value, index - 1) == 'A') || 
contains(value, index - 1, 5, "UCCEE", "UCCES")) {
//-- "accident", "accede", "succeed" --//
result.append("KS");
} else {
//-- "bacci", "bertucci", other Italian --//
result.append('X');
}
index += 3;
} else {// Pierce's rule
result.append('K');
index += 2;
}

return index;
}

/**
 * Handles 'CH' cases
 */
private int handleCH(String value, 
 DoubleMetaphoneResult result, 
 int index) {
if (index > 0 && contains(value, index, 4, "CHAE")) {   // Michael
result.append('K', 'X');
return index + 2;
} else if (conditionCH0(value, index)) {
//-- Greek roots ("chemistry", "chorus", etc.) --//
result.append('K');
return index + 2;
} else if (conditionCH1(value, index)) {
//-- Germanic, Greek, or otherwise 'ch' for 'kh' sound --//
result.append('K');
return index + 2;
} else {
if (index > 0) {
if (contains(value, 0, 2, "MC")) {
result.append('K');
} else {
result.append('X', 'K');
}
} else {
result.append('X');
}
return index + 2;
}
}

/**
 * Handles 'D' cases
 */
private int handleD(String value, 
DoubleMetaphoneResult result, 
int index) {
if (contains(value, index, 2, "DG")) {
//-- "Edge" --//
if (contains(value, index + 2, 1, "I", "E", "Y")) {
result.append('J');
index += 3;
//-- "Edgar" --//
} else {
result.append("TK");
index += 2;
}
} else if (contains(value, index, 2, "DT", "DD")) {
result.append('T');
index += 2;
} else {
result.append('T');
index++;
}
return index;
}

/**
 * Handles 'G' cases
 */
private int handleG(String value, 
DoubleMetaphoneResult result, 
int index, 
boolean slavoGermanic) {
if (charAt(value, index + 1) == 'H') {
index = handleGH(value, result, index);
} else if (charAt(value, index + 1) == 'N') {
if (index == 1 && isVowel(charAt(value, 0)) && !slavoGermanic) {
result.append("KN", "N");
} else if (!contains(value, index + 2, 2, "EY") && 
   charAt(value, index + 1) != 'Y' && !slavoGermanic) {
result.append("N", "KN");
} else {
result.append("KN");
}
index = index + 2;
} else if (contains(value, index + 1, 2, "LI") && !slavoGermanic) {
result.append("KL", "L");
index += 2;
} else if (index == 0 && (charAt(value, index + 1) == 'Y' || contains(value, index + 1, 2, ES_EP_EB_EL_EY_IB_IL_IN_IE_EI_ER))) {
//-- -ges-, -gep-, -gel-, -gie- at beginning --//
result.append('K', 'J');
index += 2;
} else if ((contains(value, index + 1, 2, "ER") || 
charAt(value, index + 1) == 'Y') &&
   !contains(value, 0, 6, "DANGER", "RANGER", "MANGER") &&
   !contains(value, index - 1, 1, "E", "I") && 
   !contains(value, index - 1, 3, "RGY", "OGY")) {
//-- -ger-, -gy- --//
result.append('K', 'J');
index += 2;
} else if (contains(value, index + 1, 1, "E", "I", "Y") || 
   contains(value, index - 1, 4, "AGGI", "OGGI")) {
//-- Italian "biaggi" --//
if ((contains(value, 0 ,4, "VAN ", "VON ") || contains(value, 0, 3, "SCH")) || contains(value, index + 1, 2, "ET")) {
//-- obvious germanic --//
result.append('K');
} else if (contains(value, index + 1, 3, "IER")) {
result.append('J');
} else {
result.append('J', 'K');
}
index += 2;
} else if (charAt(value, index + 1) == 'G') {
index += 2;
result.append('K');
} else {
index++;
result.append('K');
}
return index;
}

/**
 * Handles 'GH' cases
 */
private int handleGH(String value, 
 DoubleMetaphoneResult result, 
 int index) {
if (index > 0 && !isVowel(charAt(value, index - 1))) {
result.append('K');
index += 2;
} else if (index == 0) {
if (charAt(value, index + 2) == 'I') {
result.append('J');
} else {
result.append('K');
}
index += 2;
} else if ((index > 1 && contains(value, index - 2, 1, "B", "H", "D")) ||
   (index > 2 && contains(value, index - 3, 1, "B", "H", "D")) ||
   (index > 3 && contains(value, index - 4, 1, "B", "H"))) {
//-- Parker's rule (with some further refinements) - "hugh"
index += 2;
} else {
if (index > 2 && charAt(value, index - 1) == 'U' && 
contains(value, index - 3, 1, "C", "G", "L", "R", "T")) {
//-- "laugh", "McLaughlin", "cough", "gough", "rough", "tough"
result.append('F');
} else if (index > 0 && charAt(value, index - 1) != 'I') {
result.append('K');
}
index += 2;
}
return index;
}

/**
 * Handles 'H' cases
 */
private int handleH(String value, 
DoubleMetaphoneResult result, 
int index) {
//-- only keep if first & before vowel or between 2 vowels --//
if ((index == 0 || isVowel(charAt(value, index - 1))) && 
isVowel(charAt(value, index + 1))) {
result.append('H');
index += 2;
//-- also takes car of "HH" --//
} else {
index++;
}
return index;
}

/**
 * Handles 'J' cases
 */
private int handleJ(String value, DoubleMetaphoneResult result, int index, 
boolean slavoGermanic) {
if (contains(value, index, 4, "JOSE") || contains(value, 0, 4, "SAN ")) {
//-- obvious Spanish, "Jose", "San Jacinto" --//
if ((index == 0 && (charAt(value, index + 4) == ' ') || 
 value.length() == 4) || contains(value, 0, 4, "SAN ")) {
result.append('H');
} else {
result.append('J', 'H');
}
index++;
} else {
if (index == 0 && !contains(value, index, 4, "JOSE")) {
result.append('J', 'A');
} else if (isVowel(charAt(value, index - 1)) && !slavoGermanic && 
  (charAt(value, index + 1) == 'A' || charAt(value, index + 1) == 'O')) {
result.append('J', 'H');
} else if (index == value.length() - 1) {
result.append('J', ' ');
} else if (!contains(value, index + 1, 1, L_T_K_S_N_M_B_Z) && !contains(value, index - 1, 1, "S", "K", "L")) {
result.append('J');
}

if (charAt(value, index + 1) == 'J') {
index += 2;
} else {
index++;
}
}
return index;
}

/**
 * Handles 'L' cases
 */
private int handleL(String value, 
DoubleMetaphoneResult result, 
int index) {
if (charAt(value, index + 1) == 'L') {
if (conditionL0(value, index)) {
result.appendPrimary('L');
} else {
result.append('L');
}
index += 2;
} else {
index++;
result.append('L');
}
return index;
}

/**
 * Handles 'P' cases
 */
private int handleP(String value, 
DoubleMetaphoneResult result, 
int index) {
if (charAt(value, index + 1) == 'H') {
result.append('F');
index += 2;
} else {
result.append('P');
index = contains(value, index + 1, 1, "P", "B") ? index + 2 : index + 1;
}
return index;
}

/**
 * Handles 'R' cases
 */
private int handleR(String value, 
DoubleMetaphoneResult result, 
int index, 
boolean slavoGermanic) {
if (index == value.length() - 1 && !slavoGermanic && 
contains(value, index - 2, 2, "IE") && 
!contains(value, index - 4, 2, "ME", "MA")) {
result.appendAlternate('R');
} else {
result.append('R');
}
return charAt(value, index + 1) == 'R' ? index + 2 : index + 1;
}

/**
 * Handles 'S' cases
 */
private int handleS(String value, 
DoubleMetaphoneResult result, 
int index, 
boolean slavoGermanic) {
if (contains(value, index - 1, 3, "ISL", "YSL")) {
//-- special cases "island", "isle", "carlisle", "carlysle" --//
index++;
} else if (index == 0 && contains(value, index, 5, "SUGAR")) {
//-- special case "sugar-" --//
result.append('X', 'S');
index++;
} else if (contains(value, index, 2, "SH")) {
if (contains(value, index + 1, 4, 
 "HEIM", "HOEK", "HOLM", "HOLZ")) {
//-- germanic --//
result.append('S');
} else {
result.append('X');
}
index += 2;
} else if (contains(value, index, 3, "SIO", "SIA") || contains(value, index, 4, "SIAN")) {
//-- Italian and Armenian --//
if (slavoGermanic) {
result.append('S');
} else {
result.append('S', 'X');
}
index += 3;
} else if ((index == 0 && contains(value, index + 1, 1, "M", "N", "L", "W")) || contains(value, index + 1, 1, "Z")) {
//-- german & anglicisations, e.g. "smith" match "schmidt" //
// "snider" match "schneider" --//
//-- also, -sz- in slavic language altho in hungarian it //
//   is pronounced "s" --//
result.append('S', 'X');
index = contains(value, index + 1, 1, "Z") ? index + 2 : index + 1;
} else if (contains(value, index, 2, "SC")) {
index = handleSC(value, result, index);
} else {
if (index == value.length() - 1 && contains(value, index - 2, 
2, "AI", "OI")){
//-- french e.g. "resnais", "artois" --//
result.appendAlternate('S');
} else {
result.append('S');
}
index = contains(value, index + 1, 1, "S", "Z") ? index + 2 : index + 1;
}
return index;
}

/**
 * Handles 'SC' cases
 */
private int handleSC(String value, 
 DoubleMetaphoneResult result, 
 int index) {
if (charAt(value, index + 2) == 'H') {
//-- Schlesinger's rule --//
if (contains(value, index + 3, 
 2, "OO", "ER", "EN", "UY", "ED", "EM")) {
//-- Dutch origin, e.g. "school", "schooner" --//
if (contains(value, index + 3, 2, "ER", "EN")) {
//-- "schermerhorn", "schenker" --//
result.append("X", "SK");
} else {
result.append("SK");
}
} else {
if (index == 0 && !isVowel(charAt(value, 3)) && charAt(value, 3) != 'W') {
result.append('X', 'S');
} else {
result.append('X');
}
}
} else if (contains(value, index + 2, 1, "I", "E", "Y")) {
result.append('S');
} else {
result.append("SK");
}
return index + 3;
}

/**
 * Handles 'T' cases
 */
private int handleT(String value, 
DoubleMetaphoneResult result, 
int index) {
if (contains(value, index, 4, "TION")) {
result.append('X');
index += 3;
} else if (contains(value, index, 3, "TIA", "TCH")) {
result.append('X');
index += 3;
} else if (contains(value, index, 2, "TH") || contains(value, index, 
   3, "TTH")) {
if (contains(value, index + 2, 2, "OM", "AM") || 
//-- special case "thomas", "thames" or germanic --//
contains(value, 0, 4, "VAN ", "VON ") || 
contains(value, 0, 3, "SCH")) {
result.append('T');
} else {
result.append('0', 'T');
}
index += 2;
} else {
result.append('T');
index = contains(value, index + 1, 1, "T", "D") ? index + 2 : index + 1;
}
return index;
}

/**
 * Handles 'W' cases
 */
private int handleW(String value, 
DoubleMetaphoneResult result, 
int index) {
if (contains(value, index, 2, "WR")) {
//-- can also be in middle of word --//
result.append('R');
index += 2;
} else {
if (index == 0 && (isVowel(charAt(value, index + 1)) || 
   contains(value, index, 2, "WH"))) {
if (isVowel(charAt(value, index + 1))) {
//-- Wasserman should match Vasserman --//
result.append('A', 'F');
} else {
//-- need Uomo to match Womo --//
result.append('A');
}
index++;
} else if ((index == value.length() - 1 && isVowel(charAt(value, index - 1))) ||
   contains(value, index - 1, 
5, "EWSKI", "EWSKY", "OWSKI", "OWSKY") ||
   contains(value, 0, 3, "SCH")) {
//-- Arnow should match Arnoff --//
result.appendAlternate('F');
index++;
} else if (contains(value, index, 4, "WICZ", "WITZ")) {
//-- Polish e.g. "filipowicz" --//
result.append("TS", "FX");
index += 4;
} else {
index++;
}
}
return index;
}

/**
 * Handles 'X' cases
 */
private int handleX(String value, 
DoubleMetaphoneResult result, 
int index) {
if (index == 0) {
result.append('S');
index++;
} else {
if (!((index == value.length() - 1) && 
  (contains(value, index - 3, 3, "IAU", "EAU") || 
   contains(value, index - 2, 2, "AU", "OU")))) {
//-- French e.g. breaux --//
result.append("KS");
}
index = contains(value, index + 1, 1, "C", "X") ? index + 2 : index + 1;
}
return index;
}

/**
 * Handles 'Z' cases
 */
private int handleZ(String value, DoubleMetaphoneResult result, int index, 
boolean slavoGermanic) {
if (charAt(value, index + 1) == 'H') {
//-- Chinese pinyin e.g. "zhao" or Angelina "Zhang" --//
result.append('J');
index += 2;
} else {
if (contains(value, index + 1, 2, "ZO", "ZI", "ZA") || (slavoGermanic && (index > 0 && charAt(value, index - 1) != 'T'))) {
result.append("S", "TS");
} else {
result.append('S');
}
index = charAt(value, index + 1) == 'Z' ? index + 2 : index + 1;
}
return index;
}

//-- BEGIN CONDITIONS --//

/**
 * Complex condition 0 for 'C'
 */
private boolean conditionC0(String value, int index) {
if (contains(value, index, 4, "CHIA")) {
return true;
} else if (index <= 1) {
return false;
} else if (isVowel(charAt(value, index - 2))) {
return false;
} else if (!contains(value, index - 1, 3, "ACH")) {
return false;
} else {
char c = charAt(value, index + 2);
return (c != 'I' && c != 'E') ||
contains(value, index - 2, 6, "BACHER", "MACHER");
}
}

/**
 * Complex condition 0 for 'CH'
 */
private boolean conditionCH0(String value, int index) {
if (index != 0) {
return false;
} else if (!contains(value, index + 1, 5, "HARAC", "HARIS") && 
   !contains(value, index + 1, 3, "HOR", "HYM", "HIA", "HEM")) {
return false;
} else if (contains(value, 0, 5, "CHORE")) {
return false;
} else {
return true;
}
}

/**
 * Complex condition 1 for 'CH'
 */
private boolean conditionCH1(String value, int index) {
return ((contains(value, 0, 4, "VAN ", "VON ") || contains(value, 0, 
   3, "SCH")) ||
contains(value, index - 2, 6, "ORCHES", "ARCHIT", "ORCHID") ||
contains(value, index + 2, 1, "T", "S") ||
((contains(value, index - 1, 1, "A", "O", "U", "E") || index == 0) &&
 (contains(value, index + 2, 1, L_R_N_M_B_H_F_V_W_SPACE) || index + 1 == value.length() - 1)));
}

/**
 * Complex condition 0 for 'L'
 */
private boolean conditionL0(String value, int index) {
if (index == value.length() - 3 && 
contains(value, index - 1, 4, "ILLO", "ILLA", "ALLE")) {
return true;
} else if ((contains(value, value.length() - 2, 2, "AS", "OS") || 
contains(value, value.length() - 1, 1, "A", "O")) &&
   contains(value, index - 1, 4, "ALLE")) {
return true;
} else {
return false;
}
}

/**
 * Complex condition 0 for 'M'
 */
private boolean conditionM0(String value, int index) {
if (charAt(value, index + 1) == 'M') {
return true;
}
return contains(value, index - 1, 3, "UMB") &&
((index + 1) == value.length() - 1 || contains(value,
index + 2, 2, "ER"));
}

//-- BEGIN HELPER FUNCTIONS --//

/**
 * Determines whether or not a value is of slavo-germanic orgin. A value is
 * of slavo-germanic origin if it contians any of 'W', 'K', 'CZ', or 'WITZ'.
 */
private boolean isSlavoGermanic(String value) {
return value.indexOf('W') > -1 || value.indexOf('K') > -1 || 
value.indexOf("CZ") > -1 || value.indexOf("WITZ") > -1;
}

/**
 * Determines whether or not a character is a vowel or not
 */
private boolean isVowel(char ch) {
return VOWELS.indexOf(ch) != -1;
}

/**
 * Determines whether or not the value starts with a silent letter.  It will
 * return <code>true</code> if the value starts with any of 'GN', 'KN',
 * 'PN', 'WR' or 'PS'.
 */
private boolean isSilentStart(String value) {
boolean result = false;
for (int i = 0; i < SILENT_START.length; i++) {
if (value.startsWith(SILENT_START[i])) {
result = true;
break;
}
}
return result;
}

/**
 * Cleans the input
 */
private String cleanInput(String input) {
if (input == null) {
return null;
}
input = input.trim();
if (input.length() == 0) {
return null;
}
return input.toUpperCase(java.util.Locale.ENGLISH);
}

/**
 * Gets the character at index <code>index</code> if available, otherwise
 * it returns <code>Character.MIN_VALUE</code> so that there is some sort
 * of a default
 */
protected char charAt(String value, int index) {
if (index < 0 || index >= value.length()) {
return Character.MIN_VALUE;
} 
return value.charAt(index);
}

/**
 * Shortcut method with 1 criteria
 */
private static boolean contains(String value, int start, int length, 
String criteria) {
return contains(value, start, length, 
new String[] { criteria });
}

/**
 * Shortcut method with 2 criteria
 */
private static boolean contains(String value, int start, int length, 
String criteria1, String criteria2) {
return contains(value, start, length, 
new String[] { criteria1, criteria2 });
}

/**
 * Shortcut method with 3 criteria
 */
private static boolean contains(String value, int start, int length, 
String criteria1, String criteria2, 
String criteria3) {
return contains(value, start, length, 
new String[] { criteria1, criteria2, criteria3 });
}

/**
 * Shortcut method with 4 criteria
 */
private static boolean contains(String value, int start, int length, 
String criteria1, String criteria2, 
String criteria3, String criteria4) {
return contains(value, start, length, 
new String[] { criteria1, criteria2, criteria3, 
   criteria4 });
}

/**
 * Shortcut method with 5 criteria
 */
private static boolean contains(String value, int start, int length, 
String criteria1, String criteria2, 
String criteria3, String criteria4, 
String criteria5) {
return contains(value, start, length, 
new String[] { criteria1, criteria2, criteria3, 
   criteria4, criteria5 });
}

/**
 * Shortcut method with 6 criteria
 */
private static boolean contains(String value, int start, int length, 
String criteria1, String criteria2, 
String criteria3, String criteria4, 
String criteria5, String criteria6) {
return contains(value, start, length, 
new String[] { criteria1, criteria2, criteria3, 
   criteria4, criteria5, criteria6 });
}

/**
 * Determines whether <code>value</code> contains any of the criteria starting at index <code>start</code> and
 * matching up to length <code>length</code>
 */
protected static boolean contains(String value, int start, int length, 
  String[] criteria) {
boolean result = false;
if (start >= 0 && start + length <= value.length()) {
String target = value.substring(start, start + length);

for (int i = 0; i < criteria.length; i++) {
if (target.equals(criteria[i])) {
result = true;
break;
}
}
}
return result;
}

//-- BEGIN INNER CLASSES --//

/**
 * Inner class for storing results, since there is the optional alternate
 * encoding.
 */
public class DoubleMetaphoneResult {

private StringBuffer primary = new StringBuffer(getMaxCodeLen());
private StringBuffer alternate = new StringBuffer(getMaxCodeLen());
private int maxLength;

public DoubleMetaphoneResult(int maxLength) {
this.maxLength = maxLength;
}

public void append(char value) {
appendPrimary(value);
appendAlternate(value);
}

public void append(char primary, char alternate) {
appendPrimary(primary);
appendAlternate(alternate);
}

public void appendPrimary(char value) {
if (this.primary.length() < this.maxLength) {
this.primary.append(value);
}
}

public void appendAlternate(char value) {
if (this.alternate.length() < this.maxLength) {
this.alternate.append(value);
}
}

public void append(String value) {
appendPrimary(value);
appendAlternate(value);
}

public void append(String primary, String alternate) {
appendPrimary(primary);
appendAlternate(alternate);
}

public void appendPrimary(String value) {
int addChars = this.maxLength - this.primary.length();
if (value.length() <= addChars) {
this.primary.append(value);
} else {
this.primary.append(value.substring(0, addChars));
}
}

public void appendAlternate(String value) {
int addChars = this.maxLength - this.alternate.length();
if (value.length() <= addChars) {
this.alternate.append(value);
} else {
this.alternate.append(value.substring(0, addChars));
}
}

public String getPrimary() {
return this.primary.toString();
}

public String getAlternate() {
return this.alternate.toString();
}

public boolean isComplete() {
return this.primary.length() >= this.maxLength && 
this.alternate.length() >= this.maxLength;
}
}
}
